Field of the Invention
The present disclosure relates to an electrophotographic photoconductor, and an image forming apparatus and a process cartridge both using the electrophotographic photoconductor.
Description of the Related Art
In an image forming method using an image forming apparatus, an image is formed by performing steps, such as a charging step, an exposure step, a developing step, a transfer step, and a charge-eliminating step, on an electrophotographic photoconductor (may be referred to as a “photoconductor” hereinafter). The electrophotographic photoconductor typically has a structure including a support, an undercoat layer formed on the support, and a photoconductive layer disposed on the undercoat layer. Organic materials are widely used for the undercoat layer and the photoconductive layer because of advantages, such as flexibility, thermal stability, and film formation properties.
When the electrophotographic photoconductor is used over a long period, deteriorations in electrical properties, such as reduction in chargeability due to electrostatic load, gradually occur because a charging step and a charge-eliminating step are repeatedly performed on the electrophotographic photoconductor. It has been known that deteriorations of the electrical properties largely influence image quality of output images, leading to serious problems, such as low image density, occurrences of background fog (may be also referred to as background deposition, fogging, or black spots, hereinafter), and low uniformity of images when continuously output.
In order to stabilize electrical properties of the electrophotographic photoconductor and image quality, for example, proposed is an electrophotographic photoconductor including an undercoat layer to which metal oxide particles and oximes are added (see, for example, Japanese Unexamined Patent Application Publication No. 2014-66756). However, the proposed electrophotographic photoconductor cannot maintain stable electrical properties and image quality when used over a long period.
Accordingly, there is a strong demand for developing an electrophotographic photoconductor that can obtain sufficiently stable electrical properties and image quality over a long period.